US vice-president Mike Pence, DUP leader Arlene Foster, and Sinn Féin president Mary Lou McDonald were also in attendance.

Speaking about his earlier private meeting with Mr Varadkar, the US president said: “We discussed a lot of things, in particular we talked about Brexit, something that turned out to be a little more complex than they thought it be.

“But it will all work out, everything does, one way or the other.

“You’ve got a very interesting view on it, and I appreciate you letting me know what’s going on over there.

“(It’s) a very tough situation.”Mr Trump spoke during the lunch (Brian Lawless/PA)

He added: “The United States and Ireland are bound together with ties of both kinship and friendship, a really great friendship.

“Today, our relationship is as strong and resilient as the great Irish people are strong and resilient.”

Mr Varadkar thanked the Friends of Ireland caucus in Congress for the “vital help” in protecting the Good Friday Agreement.

The organisation was founded by Irish-American politicians to support peace and reconciliation in Northern Ireland.

Mr Varadkar added: “The Irish people have always had a dialogue with the American people. It is genuine, it is warm, and it has stood the test of time.Mr Varadkar presents Speaker of the House of Representatives Nancy Pelosi with a copy of a letter signed by more than 300 congressman written in 1937 to congratulate Ireland on its new constitution (Brian Lawless/PA)

“Your political and civic leaders – of all parties and backgrounds – helped shape the country that Ireland is today.

“And I want to say on behalf of the Irish government and behalf of the Irish people, that we thank the Friends of Ireland caucus in Congress for their vital help at this critical time to protect the provisions of the Good Friday Agreement and ensure there is no return to a hard border on the island of Ireland, whatever happens with Brexit.

“Madam Speaker, President Reagan once said that ‘a people free to choose will always choose peace’. He was right, and I know the land of liberty will continue to protect that fundamental freedom.”